Washington: Regular exercise may help decrease violent behaviour among adolescent girls, according to a new study.Researchers from Columbia University analysed results of a 2008 survey completed by 1,312 students at four inner-city high schools in New York to determine if there was an association between regular exercise and violence-related behaviours.

The survey included questions on how often students exercised, how many sit-ups they did and the time of their longest run in the past four weeks as well as whether they played on an organised sports team in the past year.

Students were also asked if they had carried a weapon in the past 30 days or if they were in a physical fight or in a gang in the past year.

Nearly three-quarters of the respondents were Latino, and 19 per cent were black. Fifty-six per cent were female.

Results showed that females who reported exercising regularly had decreased odds of being involved in violence-related behaviours.

Females who exercised more than 10 days in the last month had decreased odds of being in a gang.

Those who did more than 20 sit-ups in the past four weeks had decreased odds of carrying a weapon or being in a gang.

Females reporting running more than 20 minutes the last time they ran had decreased odds of carrying a weapon.

Those who participated in team sports in the past year had decreased odds of carrying a weapon, being in a fight or being in a gang.

In males, none of the measures of exercise was associated with a decrease in violence-related behaviours, which could be because a larger proportion of males than females did not answer all of the survey questions, said lead author Noe D Romo, primary care research fellow in community health in theDepartment of Child and Adolescent Health at Columbia University, New York.

The study was presented at the Pediatric Academic Societies (PAS) annual meeting in Washington, DC.